Add Endpoint to get all Credits for a TV Show, no matter the Season.

Currently, to get all Main Credits, you have to iterate each
Season to find each credit, for shows that have cast and crew
members come and go.
I would like to get all the main cast members for shows like Doctor
Who, where the main cast changes every couple of seasons.
Perhaps if there was an Array property of Seasons in the Credit
Object, it would be an easier way of fetching this information.

That would help provide this useful information in an efficient
manner, and means that Services like Trakt.TV, would have a better
idea of the Actors, as you see here: https://trakt.tv/shows/doctor-who-2005

Currently on Trakt.TV, if you look up Peter Capaldi, there is no
reference to his actual credit on the Show (Although that is
probably an implementation flaw), Having access to this information
without looking up seasons would be more effective.